Battery drain in MB C320

HELP 2000 Z3 Battery Drain - Bimmerfest - BMW Forums

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Feb 18, 2007 - 7 posts - ‎6 authors
HELP 2000 Z3 Battery Drain E36/7 Z3 (1996-2002) ... Something is draining the battery. ... Posts: 55. Mein Auto: 2000 BMW Z3 2.8 Roadster. z3 1.9 battery drain (fuse 31)
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The problem is that an electrical component in the BMW that should be dormant when the vehicle is shut down is actively drawing power.
The only way to track it down is to have tests run to see which circuit is drawing excessive power because there are numerous components that might be the cause.

You can learn more here...........
Solving Automotive Electrical Problems

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Check to be sure the trunk is closing all the way. It happened once to me - someone slammed my trunk shut and after that it would not close all the way. Never slam a Mercedes trunk!

Here are the general instructions to find a battery parasitic drain, it is different for each problem and there is no magic bullet fix.

Instructions

• Charge your battery if necessary. Dead batteries (and even weak ones) don't give accurate results on a draw test. The dome light is a good indicator of battery strength. If the light is weak, pulsating or refuses to turn on, you'll need to charge the battery.
  
• 2Shut off everything in the car. Pull the keys out of the ignition. Ensure all service lights are off, lighted compartments closed and doors shut. Open the hood, and disconnect the trouble light underneath if your vehicle has one. Wait for 30 minutes before moving on to Step 3. (This enables normal drain from interior components to finish cycling.)
  
• 3Set your battery tester to 10 amps DC. Disconnect your positive battery connection (red cable) and position it safely away from metal components. Connect the meter's positive probe to the battery's positive post while simultaneously holding the negative probe in the air; keep it away from anything metal.
  
• 4Place the negative probe on the end of the removed positive cable to complete the circuit. Yes, you're putting a negative on a positive. Yes, this is ok. If you have a severe drain, you're likely to pop a fuse or two-identifying your problem.
  
• 5Check the meter reading. A normal reading is usually under .035 amps. If you have a minor drain that causes a higher reading, you'll need to check each component.
  
• 6Remove the first fuse in the box, and check to see if the load problem is resolved. If not, replace the fuse and check the next one. Repeat the process with all fuses. If the fuses check out fine, you have a wiring problem.
  
• 7Remove the tester and reconnect the battery. Follow the hot wire to the next connection. Remove the positive cable and connect the positive probe of the tester in its place. Connect the negative probe to a metal object. Check the meter. If the drain isn't resolved, reconnect as normal and follow the hot wire to the next connection. Repeat this step at each connection point until you narrow down the problem.
  

Duplicate posting

Have the vehicle scanned for error codes.

Check for hidden things that may be staying on. Trunk lamps, under hood lamps, and lighted visor mirrors, as well as glove box lamps are many times the culprits.

radio needs the code putting into it

First of all, have battery "Load tested", then double check alternator is charging which I assume it is. If battery weak, replace it, but remember, it should be load tested when fully charged. If not battery, then you'll need to check for amperage draw on system when everything shut off, and isolate circuit causing draw. If you get that far & aren't sure how to do it, get back to us.

one of the problems could be , you have a bad drain on battery, check charging system,if you disconect battery and hook it back up does it ark if so check all elecrical components for drain